JP3361257B2 - Heavy duty pneumatic tires - Google Patents
Heavy duty pneumatic tiresInfo
- Publication number
- JP3361257B2 JP3361257B2 JP29438697A JP29438697A JP3361257B2 JP 3361257 B2 JP3361257 B2 JP 3361257B2 JP 29438697 A JP29438697 A JP 29438697A JP 29438697 A JP29438697 A JP 29438697A JP 3361257 B2 JP3361257 B2 JP 3361257B2
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- JP
- Japan
- Prior art keywords
- groove
- tire
- lateral
- tread
- lateral groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【発明の属する技術分野】本発明は、摩耗初期〜中期に
亘けるウエットグリップ不足を改善でき、特にダンプト
ラックなどの建設車両用として好適な重荷重用空気入り
タイヤに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy-duty pneumatic tire capable of improving wet grip insufficiency in the early to middle stages of wear and suitable for construction vehicles such as dump trucks.
【０００２】[0002]
【従来の技術、及び発明が解決しようとする課題】土を
主体とする地道等の不整地で用いられる、例えばダンプ
トラックなどの建設車両用等の重荷重用空気入りタイヤ
にあっては、不整地での駆動・制動性を確保するため、
図６に示すように、トレッド縁Ｔｅからタイヤ赤道Ｃの
近傍までのびる超深溝タイプの長いラグ溝ａ（横溝）を
形成したラグパターンが多用されている。2. Description of the Related Art For heavy-duty pneumatic tires for construction vehicles such as dump trucks, which are used on rough terrain such as soil-based roads, the rough terrain is used. In order to secure driving / braking performance at
As shown in FIG. 6, a lug pattern in which a long lug groove a (lateral groove) of an ultra-deep groove type extending from the tread edge Te to the vicinity of the tire equator C is formed is often used.
【０００３】しかしながら、この種のタイヤでは、トレ
ッドゴムが厚く形成されているため、トレッド内部まで
加硫を行うためにはトレッド面が加硫過剰（過加硫）と
なり、強力、弾性率等のゴム物性を大きく低下する加硫
戻りという現象を発生する。その結果、この過加硫のゴ
ムが摩滅する摩耗中期以降においては、所望の物性のゴ
ム部分が接地するため充分な駆動・制動性を発揮するも
のの、前記過加硫のゴムが接地する摩耗初期において
は、特に雨天時に良路及び作業現場等における鉄板路、
溝の蓋上などを走行する際、スリップを誘発するなどウ
エットグリップ性能を不充分としていた。なおこの傾向
は、トレッドゴムに耐摩耗性や低発熱性に優れる天然ゴ
ムを採用したとき、より顕著に表れる。However, in this type of tire, since the tread rubber is thickly formed, in order to vulcanize the inside of the tread, the tread surface becomes excessively vulcanized (overvulcanized), and the strength, elastic modulus, etc. A phenomenon called reversion occurs, which greatly deteriorates rubber physical properties. As a result, in the middle period of wear after the overvulcanized rubber is worn out, the rubber portion having desired physical properties is grounded, so that sufficient driving / braking performance is exhibited, but the initial wear stage in which the overvulcanized rubber is grounded In particular, especially in rainy weather and iron roads at work sites,
When driving on the lid of the groove, slipping was induced and wet grip performance was insufficient. It should be noted that this tendency becomes more remarkable when a natural rubber having excellent wear resistance and low heat buildup is adopted as the tread rubber.
【０００４】そこで本発明者らは、前記図６に一点鎖線
で示すように、ラグパターン上に、浅底の縦溝ｂを形成
し、過加硫ゴムが残存する摩耗初期〜中期においてのみ
排水性を発揮せしめ、ウエットグリップ不足を補うこと
を案出した。Therefore, the inventors of the present invention formed a shallow bottom vertical groove b on the lug pattern as shown by the one-dot chain line in FIG. 6 above, and drained water only in the early to middle stages of wear when the overvulcanized rubber remained. It has been devised to make full use of its performance and compensate for the lack of wet grip.
【０００５】しかし、この縦溝ｂは、ラグ溝ａにおける
横方向エッジ成分を減ずるため、不整地における駆動・
制動性低下の要因となり、摩耗初期〜中期においては、
ラグ溝ａが充分深く高い駆動・制動性を発揮しうるとは
いえ、タイヤ全体として駆動・制動性能の低下傾向を招
く。又ラグ溝深さが半減する摩耗中期以降においては、
縦溝ｂ自体が消失することにより前記駆動・制動性能の
低下は解消され、又耐パンク性能も維持されるが、縦溝
ｂが消失する前後において、排水性能の変化が大きくな
るという、解決しなければならない問題が判明した。However, since this vertical groove b reduces the lateral edge component in the lug groove a, it is possible to drive on uneven terrain.
This will cause a decrease in braking performance, and during the early to middle stages of wear,
Although the lug groove a can exhibit a sufficiently deep and high driving / braking property, the driving / braking performance of the tire as a whole tends to deteriorate. Also, after the middle wear period when the lug groove depth is halved,
The disappearance of the vertical groove b itself eliminates the deterioration of the drive / braking performance and maintains the puncture resistance performance, but the drainage performance changes largely before and after the vertical groove b disappears. Turns out the problem must be.
【０００６】そこで本発明は、前記ラグパターン上に浅
底の縦溝を形成したタイヤにおいて、この縦溝が消失し
た時のトレッド面でのラグ溝（横溝）が、トレッド縁か
ら溝巾が一定若しくは漸減してのびる横溝主残部の内端
に、この横溝主残部の内端よりも溝巾が大な横溝広巾残
部を具えることを基本として、摩耗初期〜中期に亘ける
ウエットグリップ不足を改善しうるとともに、前記縦溝
の形成に起因する駆動・制動性の低下を抑制でき、しか
も縦溝の消失前後における排水性能の変化を低減できる
重荷重用空気入りタイヤの提供を目的としている。In view of the above, the present invention provides a tire in which a shallow bottom vertical groove is formed on the lug pattern, and the lug groove (horizontal groove) on the tread surface when the vertical groove disappears has a constant groove width from the tread edge. Or, the lack of wet grip during the early to middle stages of wear is improved based on the fact that the inner end of the main groove of the horizontal groove that is gradually reduced has a wide horizontal groove remaining part whose groove width is larger than the inner end of the main groove of the horizontal groove. In addition, it is an object of the present invention to provide a heavy-duty pneumatic tire that can suppress the deterioration of driving / braking properties due to the formation of the vertical groove and reduce the change in drainage performance before and after the vertical groove disappears.
【０００７】[0007]
【課題を解決するための手段】前記目的を達成するため
に、本発明の重荷重用空気入りタイヤは、トレッド面
に、トレッド縁で開口しかつ略タイヤ軸方向にのびると
ともに、周方向に間隔を隔てた横溝と、この横溝をタイ
ヤ赤道近傍でつなぎ周方向にのびる縦溝とを設けた重荷
重用空気入りタイヤであって、前記縦溝は、前記横溝と
交わる交わり部と、この交わり部間の主要部とからな
り、かつ該主要部の溝深さを、横溝の溝深さの３０〜６
０％としたことによる摩耗進行に伴う前記主要部の消失
によって、 前記横溝は、摩耗した前記トレッド面に、ト
レッド縁からのびかつタイヤ赤道面と平行な面内での溝
巾がタイヤ赤道に向かって一定若しくは漸減する横溝主
残部と、この横溝主残部のタイヤ赤道側の内端に連続し
かつ前記溝巾が前記横溝主残部の内端の溝巾よりも大と
なる横溝広巾残部とを有する横溝の残部を形成する形状
としたことを特徴とする。In order to achieve the above-mentioned object, a heavy duty pneumatic tire of the present invention has a tread surface which is opened at a tread edge and extends substantially in the axial direction of the tire and has a circumferential interval. A heavy load provided with separated lateral grooves and vertical grooves that connect the lateral grooves near the tire equator and extend in the circumferential direction.
In a heavy duty pneumatic tire, the vertical groove includes an intersecting portion that intersects with the lateral groove and a main portion between the intersecting portions, and the groove depth of the main portion is 30 to 30 times the groove depth of the lateral groove. 6
Disappearance of the main part as the wear progresses due to 0%
The lateral groove causes the tread surface to
Groove extending from the red edge and in a plane parallel to the tire equatorial plane
A lateral groove main remaining portion whose width is constant or gradually decreases toward the tire equator, and a groove width which is continuous with the tire equator-side inner end of the lateral groove main remaining portion and is larger than the groove width of the inner end of the lateral groove main remaining portion.
Shape to form the rest of the lateral groove having a composed transverse groove Hirohaba balance
And said that the content was.
【０００８】又請求項２に係る発明は、前記主要部が消
失したトレッド面での前記横溝が、前記横溝広巾残部に
おけるタイヤ赤道面と平行な面内での溝断面積が最大値
となる位置Ｐ０を、タイヤ赤道からトレッド巾の１０〜
２２％を隔てる範囲内に設けたことを特徴とし、かつ請
求項３に係る発明は、前記主要部が消失したトレッド面
での前記横溝において、前記横溝広巾残部におけるタイ
ヤ赤道面と平行な面内での溝断面積が、前記横溝主残部
の内端の溝断面積よりも大きい大容積部分のタイヤ軸方
向の長さは、前記トレッド巾の５〜１０％であることを
特徴とする。 [0008] The invention according to claim 2, wherein the transverse grooves of the tread surface of the main portion has disappeared, groove cross-sectional area at tire equatorial plane and parallel to the plane is the maximum value of the transverse grooves Hirohaba balance Position P0 is 10 to the tread width from the tire equator.
Characterized by being provided within a range that separates 22%, and
In the invention according to claim 3, in the lateral groove on the tread surface where the main portion has disappeared, the tie in the wide groove remaining portion of the lateral groove is provided.
The cross-sectional area of the groove in a plane parallel to the equatorial plane is the main remaining portion
Axial direction of large-volume part that is larger than groove cross-sectional area of inner end of
The length in the direction is 5 to 10% of the tread width.
【０００９】[0009]
【発明の実施の形態】以下、本発明の実施の形態を、図
示例とともに説明する。図１において、重荷重用空気入
りタイヤ１（以下タイヤ１という）は、トレッド部２
と、その両端からタイヤ半径方向内側に向けてのびるサ
イドウォール部３と、各サイドウォール部３のタイヤ半
径方向内側端に位置するビード部４とを有し、本例で
は、サイズ１１Ｒ２２．５の超深溝タイプのダンプトラ
ック用タイヤとして形成される。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a pneumatic tire for heavy load 1 (hereinafter referred to as tire 1) includes a tread portion 2
And sidewall portions 3 extending from both ends thereof toward the tire radial inner side, and a bead portion 4 located at the tire radial inner side end of each sidewall portion 3, and in this example, a size of 11R22.5 It is formed as an ultra-deep groove type dump truck tire.
【００１０】又タイヤ１には、前記ビード部４、４間に
カーカス６が架け渡されるとともに、このカーカス６の
外側かつトレッド部２内方にはベルト層７が周方向に巻
装される。A carcass 6 is bridged between the bead portions 4 and 4 of the tire 1, and a belt layer 7 is wound around the outside of the carcass 6 and the inside of the tread portion 2 in the circumferential direction.
【００１１】前記カーカス６は、カーカスコードをタイ
ヤ赤道Ｃに対して７０〜９０゜のコード角度で配列した
１枚以上のカーカスプライから形成され、各カーカスプ
ライは、前記トレッド部２からサイドウォール部３をへ
てビード部４のビードコア５の廻りで内側かつ外側に折
返されて係止される。前記カーカスコードとして、ナイ
ロン、ポリエステル、レーヨン、芳香族ポリアミド繊維
等からなる有機繊維コードの他、スチール繊維等からな
る無機繊維コードが使用しうる。The carcass 6 is formed of one or more carcass plies in which carcass cords are arranged at a cord angle of 70 to 90 ° with respect to the tire equator C, and each carcass ply includes the tread portion 2 to the sidewall portion. Around the bead core 5 of the bead portion 4 through 3 and folded back and locked inward and outward. As the carcass cord, an organic fiber cord made of nylon, polyester, rayon, aromatic polyamide fiber or the like, or an inorganic fiber cord made of steel fiber or the like can be used.
【００１２】本例では、カーカス６は、スチール製のカ
ーカスコードを略９０°のコード角度で配列した１枚の
カーカスプライ６Ａから形成されたものを示してい
る。。In this example, the carcass 6 is formed by one carcass ply 6A in which steel carcass cords are arranged at a cord angle of approximately 90 °. .
【００１３】前記ベルト層７は、複数のベルトプライ、
本例では、タイヤ赤道Ｃに対して、例えば４５〜７０°
程度の角度で傾けた最内となる第１のベルトプライ７Ａ
と、タイヤ赤道Ｃに対してベルトコードを１０〜２５度
の小角度で傾けた第２〜第３のベルトプライ７Ｂ、７Ｃ
とを、ベルトコードがプライ間で互いに交差するように
重ね合わせた３枚構造を具えている。The belt layer 7 comprises a plurality of belt plies,
In this example, the tire equator C is, for example, 45 to 70 °.
The innermost first belt ply 7A inclined at an angle
And the second to third belt plies 7B and 7C in which the belt cord is inclined at a small angle of 10 to 25 degrees with respect to the tire equator C.
And a belt cord are superposed so that the belt cords intersect each other between the plies.
【００１４】又タイヤ１は、図２に示すように、前記ト
レッド部２の外表面であるトレッド面２Ｓに、トレッド
縁Ｔｅで開口しかつ略タイヤ軸方向にのびる複数の横溝
Ｙと、この横溝Ｙとタイヤ赤道近傍Ｑｃで交差するとと
もに周方向にのびる一対の縦溝Ｇ、Ｇとを設けている。As shown in FIG. 2, the tire 1 has a plurality of lateral grooves Y which are open at the tread edge Te and extend in the tire axial direction on a tread surface 2S which is an outer surface of the tread portion 2, and the lateral grooves. A pair of vertical grooves G, G that intersect Y with the tire equator vicinity Qc and extend in the circumferential direction are provided.
【００１５】ここで、前記トレッド面２Ｓは、図１の如
く、タイヤ子午断面において、タイヤ赤道面に中心を有
する円弧状などの凸曲線をなし、前記トレッド縁Ｔｅ
は、このトレッド面２Ｓとサイドウオール部３の外側面
との交わり点として定義される。本例では、ワンダリン
グ性能を改善するため、トレッド面２Ｓ両端部分が斜面
で形成されたテーパーショルダ構造をなし、従って、こ
の斜面とサイドウオール部３の外側面との交点により前
記トレッド縁Ｔｅを構成する。なおトレッド部２は、前
記斜面を排除したスクエアショルダ構造の他にも、トレ
ッド面２Ｓ両端部分が円弧面で形成されたラウンドショ
ルダ構造を採用することもでき、かかる場合には、この
円弧面とサイドウオール部外側面との交点又は接点によ
り前記トレッド縁Ｔｅを構成する。Here, as shown in FIG. 1, the tread surface 2S has a convex curve such as an arc shape centered on the tire equatorial plane in the tire meridional section, and the tread edge Te is formed.
Is defined as the intersection of the tread surface 2S and the outer surface of the sidewall portion 3. In this example, in order to improve the wandering performance, a tapered shoulder structure is formed in which both end portions of the tread surface 2S are formed as sloped surfaces. Therefore, the intersection of the sloped surface and the outer surface of the side wall portion 3 causes the tread edge Te to move. Constitute. Note that the tread portion 2 can adopt a round shoulder structure in which both end portions of the tread surface 2S are formed as arc surfaces, in addition to the square shoulder structure in which the slope is removed. The tread edge Te is constituted by an intersection or a contact point with the outer surface of the sidewall portion.
【００１６】前記縦溝Ｇは、タイヤ軸方向の溝巾Ｗｇ
を、前記トレッド縁Ｔｅ、Ｔｅ間の巾であるトレッド巾
ＴＷの０．０２５倍以上、本例では、約０．０７２倍と
したジグザグ溝であって、タイヤ赤道Ｃから前記トレッ
ド巾ＴＷの２０％以下の距離を隔たる領域であるタイヤ
赤道近傍Ｑｃに、そのジグザグ中心を位置して形成され
る。なお縦溝Ｇは直線溝であっても良い。The vertical groove G has a groove width Wg in the tire axial direction.
Is a zigzag groove which is 0.025 times or more the tread width TW, which is the width between the tread edges Te, Te, and is about 0.072 times in this example, and is 20 from the tire equator C to the tread width TW. The zigzag center is formed in the vicinity of the tire equator Qc, which is an area separated by a distance equal to or less than%. The vertical groove G may be a straight groove.
【００１７】又前記横溝Ｙは、本例では、前記縦溝Ｇの
ジグザグのピッチ間隔と略等しいピッチ間隔を有して周
方向に隔設される。この横溝Ｙは、トレッド縁Ｔｅで開
口する外端Ｅｏから略タイヤ軸方向にのびる超深溝タイ
プのラグ状溝であり、前記縦溝Ｇと交わることにより、
この縦溝Ｇを、横溝Ｙとの交わり部１０と、該交わり部
１０、１０間の主要部１１とに区分する。In the present embodiment, the lateral grooves Y are circumferentially spaced with a pitch interval substantially equal to the zigzag pitch interval of the vertical grooves G. The lateral groove Y is a lug-shaped groove of an ultra-deep groove type extending in the tire axial direction from the outer end Eo opening at the tread edge Te, and by intersecting the vertical groove G,
The vertical groove G is divided into an intersection 10 with the horizontal groove Y and a main portion 11 between the intersections 10 and 10.
【００１８】なお縦溝Ｇの前記主要部１１は、その溝深
さＨｇを、前記横溝Ｙの溝深さＨｙの０．３０〜０．６
０倍とした浅底をなし、従って、摩耗中期以降において
該主要部１１は消失しうる。なお縦溝Ｇの前記溝巾Ｗｇ
が０．０２５ＴＷ未満の時、ウエットグリップ性能の補
充が不充分となり、又０．１０ＴＷを越えると駆動・制
動性の低下が顕著となるため好ましくない。他方、前記
溝深さＨｇが０．３０Ｈｙ未満の時、過加硫ゴムより早
くに縦溝Ｇが消失する恐れがあり、又横溝Ｙの溝容積が
半減する摩耗中期以降においては、縦溝Ｇの影響力が相
対的に高まるため、溝深さＨｇが０．６０Ｈｙより大で
は、駆動・制動性の大巾な低下を招く。従って、前記溝
深さＨｇを０．３０Ｈｙ〜０．５０Ｈｙとするのが好ま
しい。The groove depth Hg of the main portion 11 of the vertical groove G is 0.30 to 0.6 of the groove depth Hy of the lateral groove Y.
It has a shallow bottom of 0 times, and therefore, the main part 11 can disappear after the middle stage of wear. The groove width Wg of the vertical groove G
Is less than 0.025 TW, replenishment of wet grip performance becomes insufficient, and if it exceeds 0.10 TW, driving / braking properties are significantly deteriorated, which is not preferable. On the other hand, when the groove depth Hg is less than 0.30 Hy, the vertical groove G may disappear earlier than the over-vulcanized rubber, and after the middle wear period when the groove volume of the horizontal groove Y is halved, the vertical groove G Therefore, if the groove depth Hg is larger than 0.60Hy, the driving / braking performance will be significantly reduced. Therefore, it is preferable that the groove depth Hg is 0.30 Hy to 0.50 Hy.
【００１９】ここで、前記横溝Ｙは、図１に示すよう
に、タイヤ軸方向の横溝長さＬｙの少なくとも４０％以
上の範囲に亘って、略一定の深さを有する、定深さ領域
１２を有し、この定深さ領域１２の深さをもって横溝Ｙ
の前記溝深さＨｙと定義する。この溝深さＨｙは１５ｍ
ｍ以上、本例では２０．０〜２３．０ｍｍを有する。Here, as shown in FIG. 1, the lateral groove Y has a constant depth region 12 having a substantially constant depth over at least 40% or more of the lateral groove length Ly in the tire axial direction. With a depth of this constant depth region 12
Is defined as the groove depth Hy. This groove depth Hy is 15m
m or more, in this example, 20.0 to 23.0 mm.
【００２０】又前記横溝Ｙは、溝巾中心のタイヤ軸方向
に対する角度αを１０度以下、好ましくは５度以下とす
ることにより、不整地での駆動・制動性を確保してい
る。該横溝Ｙは、直線状に形成しうるが、曲線状或いは
折れ線状に形成しても良く、この時、前記外端Ｅｏ及び
内端Ｅｉにおける溝巾中心を結んだ直線の角度αを前記
範囲としている。Further, the lateral groove Y ensures the driving / braking property on rough terrain by setting the angle α of the groove width center with respect to the tire axial direction to 10 degrees or less, preferably 5 degrees or less. The lateral groove Y may be formed in a linear shape, but may be formed in a curved shape or a polygonal line shape, and at this time, the angle α of the straight line connecting the groove width centers at the outer end Eo and the inner end Ei is within the above range. I am trying.
【００２１】又横溝Ｙの内端Ｅｉは、本例では、前記縦
溝Ｇを越えかつタイヤ赤道Ｃから控えた位置で終端し、
この内端Ｅｉ間に周方向に連続してのびるリブ状陸部１
３を形成することによって、円滑な転がり性が維持され
る。従って、前記内端Ｅｉのタイヤ赤道Ｃからの距離Ｌ
１は、円滑な転がり性のためにトレッド巾ＴＷの４％以
上が好ましい。Further, the inner end Ei of the lateral groove Y in this example ends at a position beyond the vertical groove G and away from the tire equator C,
A rib-shaped land portion 1 extending continuously in the circumferential direction between the inner ends Ei.
By forming 3, the smooth rolling property is maintained. Therefore, the distance L of the inner edge Ei from the tire equator C
1 is preferably 4% or more of the tread width TW for smooth rolling.
【００２２】又摩耗進行により縦溝Ｙの前記主要部１１
が消失した摩耗トレッド面２Ｓａにおいては、前記横溝
Ｙは、図３、４に示すように、前記トレッド縁Ｔｅから
タイヤ赤道Ｃに向かって、タイヤ周方向の溝巾を一定若
しくは漸減しながらのびる横溝主残部１５と、この横溝
主残部１５の内端１５ｅに連なる横溝広巾残部１６とか
らなる横溝の残部を形成することとなる。なお図４で
は、横溝Ｙを説明するために、溝容積部分を、逆にブロ
ック状に示している。Further, due to the progress of wear, the main portion 11 of the vertical groove Y is
In the worn tread surface 2Sa in which the tire has disappeared, the lateral groove Y extends from the tread edge Te toward the tire equator C while the groove width in the tire circumferential direction is constant or gradually reduced as shown in FIGS. a main balance 15, Toka transverse grooves Hirohaba remainder 16 leading to the inner end 15e of the lateral grooves primary balance 15
The remaining part of the lateral groove is formed. In addition, in FIG. 4, in order to explain the lateral groove Y, the groove volume portion is shown in a block shape in reverse.
【００２３】この横溝広巾残部１６は、横溝主残部１５
の前記内端１５ｅでの溝巾Ｗ１よりも大な溝巾Ｗ２を有
する広巾部分である。なお従来のラグパターンのラグ溝
ａは、図５(A)、(B)に示すように、新品時のトレッド面
及び摩耗トレッド面の何れにおいても、外端ａｏから内
端ａｉに至り溝巾が一定若しくはタイヤ赤道Ｃに向かっ
て漸減する輪郭を有し、従って横溝広巾残部１６におい
て本願と大きく相違している。The wide groove remaining portion 16 is a main groove remaining portion 15.
Is a wide portion having a groove width W2 larger than the groove width W1 at the inner end 15e. As shown in FIGS. 5 (A) and 5 (B), the lug groove a of the conventional lug pattern has a groove width from the outer end ao to the inner end ai on both the tread surface and the worn tread surface when new. Has a contour that is constant or gradually decreases toward the tire equator C, and thus is significantly different from the present invention in the lateral groove wide width remaining portion 16.
【００２４】この横溝広巾残部１６は、図４に示すよう
に、タイヤ赤道面ＣＯと平行な平面内における溝断面積
が最大値Ｓ０となる溝断面積位置Ｐ０を有し、この溝断
面積位置Ｐ０のタイヤ赤道Ｃからの距離Ｌ３をトレッド
巾ＴＷの１０〜２２％の範囲としている。この溝断面積
位置Ｐ０は、本例では、横溝広巾残部１６の溝巾Ｗ２の
最大値Ｗ２ｍの位置Ｐｍと一致している。なお横溝Ｙ
は、前記定深さ領域１２から内端Ｅｉに向かって溝深さ
を、例えば段付き状に漸減させてのびる変化深さ領域１
７を有し、従ってこの溝深さの変化状況によっては、溝
断面積位置Ｐ０と溝巾最大の位置Ｐｍとが相違する場合
も起こりうる。As shown in FIG. 4, the lateral groove wide remaining portion 16 has a groove cross-sectional area position P0 at which the groove cross-sectional area in the plane parallel to the tire equatorial plane CO becomes the maximum value S0. A distance L3 from the tire equator C of P0 is set to a range of 10 to 22% of the tread width TW. In this example, the groove cross-sectional area position P0 coincides with the position Pm of the maximum value W2m of the groove width W2 of the lateral groove wide width remaining portion 16. The lateral groove Y
Is a variable depth region 1 that extends from the constant depth region 12 toward the inner end Ei by gradually reducing the groove depth in a stepped manner.
7, the position of the groove cross-section P0 and the position Pm of the maximum groove width may differ depending on the changing situation of the groove depth.
【００２５】なお前記横溝広巾残部１６は、前記縦溝Ｇ
の交わり部１０と実質的に重なり合って、前記変化深さ
領域１７に形成される。The horizontal groove wide width remaining portion 16 is defined by the vertical groove G.
Is formed in the changing depth region 17 so as to substantially overlap the intersection portion 10 of FIG.
【００２６】又横溝広巾残部１６は、前記横溝主残部１
５の内端１５ｅでの溝断面積Ｓ１よりも大な溝断面積を
有する大容積部分１６Ａを具え、かつこの大容積部分１
６Ａの周方向の長さＬ２を、前記トレッド巾ＴＷの５〜
１０％とするとともに、前記溝断面積の最大値Ｓ０を前
記内端１５ｅでの溝断面積Ｓ１の１．５〜１．８倍の範
囲に高めている。The lateral groove wide remaining portion 16 is the lateral groove main remaining portion 1.
5 has a large volume portion 16A having a groove cross-sectional area larger than the groove cross-sectional area S1 at the inner end 15e, and this large volume portion 1
The length L2 in the circumferential direction of 6A is 5 to the tread width TW.
In addition to 10%, the maximum value S0 of the groove cross-sectional area is increased to a range of 1.5 to 1.8 times the groove cross-sectional area S1 at the inner end 15e.
【００２７】このように、溝巾がＷ２＞Ｗ１の横溝広巾
残部１６を設けているため、縦溝Ｇの消失時における排
水性を高め、ウエットグリップ性能の変化の度合いを減
じ、摩耗初期から終期に至りウエットグリップ性能を安
定して発揮しうる。特に、大容積部分１６Ａを長さＬ２
の範囲で設けているため、排水性の向上効果をより確実
かつ効果的に発揮できる。又横溝広巾残部１６は、縦溝
Ｇの消失前においては、特に溝容積の増大によって駆動
・制動性を高め、前記縦溝Ｇの形成に原因する駆動・制
動性への悪影響を相殺しうる。特に横溝広巾残部１６
が、縦溝Ｇの交わり部１０と重なり合って形成されるこ
とが、前記相殺をバランス良く行うために好ましい。As described above, since the lateral groove wide width remaining portion 16 having the groove width W2> W1 is provided, the drainage property at the time of disappearance of the vertical groove G is improved, the degree of change in wet grip performance is reduced, and the initial wear to the final stage. Therefore, the wet grip performance can be stably exhibited. Particularly, the large volume portion 16A has a length L2.
Since it is provided in the range, the drainage improvement effect can be more reliably and effectively exhibited. Further, before the vertical groove G disappears, the lateral groove wide width remaining portion 16 enhances the driving / braking property particularly by increasing the groove volume, and can cancel the adverse effect on the driving / braking property due to the formation of the vertical groove G. In particular, the wide groove remaining 16
However, it is preferable that they are formed so as to overlap with the intersecting portions 10 of the vertical grooves G in order to carry out the offsetting in a good balance.
【００２８】なお溝断面積位置Ｐ０の前記距離Ｌ３が、
トレッド巾ＴＷの１０％未満の時、及び大容積部分１６
Ａの前記長さＬ２がトレッド巾ＴＷの１０％を越えた時
には、リブ状陸部１３の剛性が局部的に減じ、偏摩耗を
誘発するとともに、転がり性能の低下を招く。逆に前記
距離Ｌ３がトレッド巾ＴＷの２２％を越えた時、及び前
記長さＬ２がトレッド巾ＴＷの５％未満の時には、前記
溝断面積位置Ｐ０での接地圧が減じかつ溝容積自体の増
加が不充分となるため、排水性及び駆動・制動性への効
果が不足傾向となる。The distance L3 at the groove cross-sectional area position P0 is
When the tread width TW is less than 10%, and the large volume portion 16
When the length L2 of A exceeds 10% of the tread width TW, the rigidity of the rib-like land portion 13 is locally reduced, causing uneven wear and lowering the rolling performance. On the contrary, when the distance L3 exceeds 22% of the tread width TW and when the length L2 is less than 5% of the tread width TW, the ground contact pressure at the groove cross-sectional area position P0 decreases and the groove volume itself. Since the increase is insufficient, the effects on drainage and driving / braking tend to be insufficient.
【００２９】又前記溝断面積の最大値Ｓ０が前記溝断面
積Ｓ１の１．５倍未満の時、排水性及び駆動・制動性へ
の効果が不足傾向となり、逆に１．８倍を越えると偏摩
耗を招来する等の問題がある。When the maximum value S0 of the groove cross-sectional area is less than 1.5 times the groove cross-sectional area S1, the effect on drainage and driving / braking properties tends to be insufficient, and conversely exceeds 1.8 times. There is a problem such as causing uneven wear.
【００３０】[0030]
【実施例】図１に示す構造をなすタイヤサイズが１１Ｒ
２２．５のダンプトラック用タイヤを表１の仕様に基づ
き試作するとともに、該試作タイヤの耐摩耗性、ウエッ
トグリップ性能、ウエット旋回性能、及び不整地での駆
動・制動性を、テストした。なお各試供タイヤとも、ト
レッドパターン以外は同構成を有している。EXAMPLE A tire having the structure shown in FIG. 1 has a tire size of 11R.
A 22.5 dump truck tire was prototyped based on the specifications shown in Table 1, and the prototype tire was tested for wear resistance, wet grip performance, wet turning performance, and drivability / braking performance on rough terrain. Each of the sample tires has the same structure except the tread pattern.
【００３１】各テスト方法は下記の通りである。
耐摩耗性
新品の各試供タイヤを、使用リム（７．５０×２２．
５）、内圧（８．０kgｆ／cm2 ）の条件でダンプ車輌の
駆動輪に装着し、２０、０００ｋｍの距離をテストコー
ス（乾燥路面）で走行した時の、摩耗量を測定しその逆
数を比較例を１００とした指数で比較した。数値が大き
いほど良好である。
ウエットグリップ性能
新品時、縦溝が消失する摩耗中期、及び横溝残高が１．
６ｍｍとなる摩耗限度時の各試供タイヤを用い、前記ダ
ンプ車輌に定荷重（１０トン）を積載した状態で、水深
３ｍｍの濡れた旋回路面を、限界走行速度でタイムトラ
イアル走行し、そのときの走行時間の逆数を比較例１の
タイヤの新品時を１００とした指数で比較した。数値が
大きいほど良好である。
ウエット旋回性能
新品時、摩耗中期、及び摩耗限度時の各試供タイヤを用
い、前記ダンプ車輌に定荷重（１０トン）を積載した状
態で、半径１００ｍのアスファルト路面に、水深３ｍ
ｍ、長さ２０ｍの水たまりを設けたコース上を、速度を
段階的に増加させながら前記車両を進入させ、横加速度
（横Ｇ）を計測し、６０km／ｈの速度における前輪の平
均横Ｇを算出した。結果は、比較例１のタイヤの新品時
を１００とした指数で比較した。数値が大きいほど良好
である。Each test method is as follows. Wear test rims (7.50 x 22.
5), wear the drive wheel of the dump vehicle under the condition of internal pressure (8.0 kgf / cm 2 ) and measure the amount of wear when running on a test course (dry road surface) for a distance of 20,000 km, and calculate the reciprocal The comparison was made using an index with Comparative Example being 100. The larger the value, the better. Wet grip performance When the product is new, the vertical groove disappears during the middle wear, and the horizontal groove balance is 1.
Using each of the trial tires at the wear limit of 6 mm, a constant load (10 tons) was loaded on the dump vehicle, and a time-trial running was performed on the wet running circuit surface with a water depth of 3 mm at the limit running speed. The reciprocal of the running time was compared by an index with the tire of Comparative Example 1 being 100 when the tire was new. The larger the value, the better. Wet turning performance Using each of the sample tires when new, in the middle of wear, and at the limit of wear, with a constant load (10 tons) loaded on the dump truck, a water depth of 3 m on an asphalt road surface with a radius of 100 m
The vehicle enters the vehicle while gradually increasing the speed on a course provided with a puddle having a length of m and a length of 20 m, the lateral acceleration (lateral G) is measured, and the average lateral G of the front wheels at a speed of 60 km / h is calculated. It was calculated. The results were compared by an index with the tire of Comparative Example 1 as 100 when the tire was new. The larger the value, the better.
【００３２】 不整地での駆動・制動性
新品時、摩耗中期、及び摩耗限度時の各試供タイヤを用
い、前記ダンプ車輛に定荷重（１０トン）を積載した状
態で、不整地（直径２〜３cmの砂利を敷き詰めた路面）
に、速度６０km／ｈにて進入させ、制動距離を測定す
る。そのときの制動距離の逆数を、比較例１のタイヤの
新品時を１００とした指数で比較した。数値が大きいほ
ど良好である。Driving / braking property on uneven terrain Using each of the sample tires at the time of new article, middle wear, and wear limit, a constant load (10 tons) was loaded on the dump vehicle, (Road surface covered with 3 cm of gravel)
To the vehicle at a speed of 60 km / h and measure the braking distance. The reciprocal of the braking distance at that time was compared by an index with 100 when the tire of Comparative Example 1 was new. The larger the value, the better.
【００３３】[0033]
【表１】 [Table 1]
【００３４】表１に示すように新品時（摩耗初期）〜摩
耗中期に亘けるウエットグリップ不足を改善でき、しか
も縦溝の形成に起因する駆動・制動性の低下を抑制しう
るのが確認できる。As shown in Table 1, it can be confirmed that the lack of wet grip from the time of new product (initial stage of wear) to the middle stage of wear can be improved, and further the deterioration of drive / braking property due to the formation of the vertical groove can be suppressed. .
【００３５】[0035]
【発明の効果】叙上の如く本発明は構成しているため、
トレッドゴムの過加硫に原因する摩耗初期〜中期に亘け
るウエットグリップ不足を改善し、ウエットグリップ性
能を全使用期間に亘り安定して発揮させるとともに、不
整地での駆動・制動性の低下を抑制しうる。Since the present invention is constructed as described above,
The wet grip shortage from the early to middle wear due to overvulcanization of the tread rubber is improved, the wet grip performance is stably exhibited over the entire usage period, and the driving / braking performance on rough terrain is reduced. Can be suppressed.
【図１】本発明の一実施例のタイヤの断面図である。FIG. 1 is a cross-sectional view of a tire according to an embodiment of the present invention.
【図２】そのトレッドパターンを示す平面図である。FIG. 2 is a plan view showing the tread pattern.
【図３】縦溝消失時の横溝を示す平面図である。FIG. 3 is a plan view showing a lateral groove when the vertical groove disappears.
【図４】縦溝消失時の横溝を示す斜視図である。FIG. 4 is a perspective view showing a lateral groove when the vertical groove disappears.
【図５】(A) 、(B) は、表１の比較例で用いたタイヤの
トレッドパターン例を示す平面図である。5 (A) and 5 (B) are plan views showing examples of tread patterns of tires used in Comparative Examples of Table 1. FIG.
【図６】従来技術を説明する線図である。FIG. 6 is a diagram illustrating a conventional technique.
２Ｓ トレッド面 １０ 交わり部 １１ 主要部 １５ 横溝主残部 １５ｅ 横溝主残部の内端 １６ 横溝広巾残部 １６Ａ 大容積部分 Ｇ 縦溝 Ｈｇ 主要部の溝深さ Ｈｙ 横溝の溝深さ Ｌ３ 大容積部分の周方向の長さ Ｑｃ タイヤ赤道近傍 Ｓ０ 横溝広巾残部における溝断面積の最大値 Ｓ１ 横溝主残部の内端における溝断面積 Ｔｅ トレッド縁 Ｙ 横溝 2S tread surface 10 fellowship 11 main parts 15 Main rest of lateral groove 15e Inner end of main part of lateral groove 16 Width remaining wide groove 16A large volume G flute Hg Groove depth of main part Hy horizontal groove depth L3 Circumferential length of large volume Qc Near the tire equator S0 Maximum value of groove cross-sectional area in the remaining wide groove S1 Groove cross-sectional area at the inner end of the main remaining portion of the lateral groove Te tread edge Y lateral groove
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭52−84607（ＪＰ，Ａ) 特開 昭47−5501（ＪＰ，Ａ) 特開 平２−179507（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B60C 11/04 - 11/13 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-52-84607 (JP, A) JP-A-47-5501 (JP, A) JP-A-2-179507 (JP, A) (58) Field (Int.Cl. 7 , DB name) B60C 11/04-11/13
Claims (3)
タイヤ軸方向にのびるとともに、周方向に間隔を隔てた
横溝と、この横溝をタイヤ赤道近傍でつなぎ周方向にの
びる縦溝とを設けた重荷重用空気入りタイヤであって、 前記縦溝は、前記横溝と交わる交わり部と、この交わり
部間の主要部とからなり、 かつ該主要部の溝深さを、横溝の溝深さの３０〜６０％
としたことによる摩耗進行に伴う前記主要部の消失によ
って、 前記横溝は、摩耗した前記トレッド面に、トレッド縁か
らのびかつタイヤ周方向での溝巾が タイヤ赤道に向かっ
て一定若しくは漸減する横溝主残部と、この横溝主残部
のタイヤ赤道側の内端に連続しかつ前記溝巾が前記横溝
主残部の内端の溝巾よりも大となる横溝広巾残部とを有
する横溝の残部を形成する形状としたことを特徴とする
重荷重用空気入りタイヤ。1. A tread surface is provided with lateral grooves which are open at the tread edge and extend substantially in the axial direction of the tire, and which are circumferentially spaced, and vertical grooves which connect the lateral grooves in the vicinity of the tire equator and extend in the circumferential direction. In the heavy-duty pneumatic tire, the vertical groove includes an intersecting portion intersecting with the lateral groove and a main portion between the intersecting portions, and the groove depth of the main portion is equal to the groove depth of the lateral groove. 30-60%
As a result, the main parts disappear as the wear progresses.
Therefore, the lateral groove is not a tread edge on the worn tread surface.
The lateral groove main remaining portion whose groove width in the tire circumferential direction is constant or gradually decreases toward the tire equator, and the tire equator side inner end of the lateral groove main remaining portion, and the groove width is within the lateral groove main remaining portion. With a wide lateral groove remaining which is larger than the groove width at the end
A heavy-duty pneumatic tire having a shape that forms the remaining portion of the lateral groove .
横溝は、前記横溝広巾残部におけるタイヤ赤道面と平行
な面内での溝断面積が最大値となる位置Ｐ０を、タイヤ
赤道からトレッド巾の１０〜２２％を隔てる範囲内に設
けたことを特徴とする請求項１記載の重荷重用空気入り
タイヤ。2. The lateral groove on the tread surface where the main portion disappears is parallel to the tire equatorial surface in the remaining portion of the lateral groove wide width.
The heavy-duty pneumatic tire according to claim 1, wherein a position P0 at which the groove cross-sectional area in the plane is maximum is provided within a range separating 10 to 22% of the tread width from the tire equator.
横溝において、前記横溝広巾残部におけるタイヤ赤道面
と平行な面内での溝断面積が、前記横溝主残部の内端の
溝断面積よりも大きい大容積部分のタイヤ軸方向の長さ
は、前記トレッド巾の５〜１０％であることを特徴とす
る請求項１又は２記載の重荷重用空気入りタイヤ。3. The tire equatorial plane in the remaining portion of the wide lateral groove in the lateral groove on the tread surface where the main portion has disappeared.
The cross-sectional area of the groove in a plane parallel to the
Tire axial length of large volume larger than groove cross section
Is 5 to 10% of the tread width, The heavy duty pneumatic tire according to claim 1 or 2, wherein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29438697A JP3361257B2 (en) | 1997-10-27 | 1997-10-27 | Heavy duty pneumatic tires |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29438697A JP3361257B2 (en) | 1997-10-27 | 1997-10-27 | Heavy duty pneumatic tires |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11129706A JPH11129706A (en) | 1999-05-18 |
| JP3361257B2 true JP3361257B2 (en) | 2003-01-07 |
Family
ID=17807063
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29438697A Expired - Lifetime JP3361257B2 (en) | 1997-10-27 | 1997-10-27 | Heavy duty pneumatic tires |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3361257B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4608111B2 (en) * | 2000-01-26 | 2011-01-05 | 株式会社ブリヂストン | Pneumatic tires for construction vehicles |
| RU2548308C1 (en) * | 2011-03-28 | 2015-04-20 | Бриджстоун Корпорейшн | Pneumatic tire |
| JP5548232B2 (en) * | 2012-05-02 | 2014-07-16 | 住友ゴム工業株式会社 | Pneumatic tire |
| JP5608709B2 (en) * | 2012-07-04 | 2014-10-15 | 株式会社ブリヂストン | tire |
| US11325423B2 (en) | 2016-01-29 | 2022-05-10 | The Yokohama Rubber Co., Ltd. | Pneumatic tire and pneumatic tire manufacturing method |
-
1997
- 1997-10-27 JP JP29438697A patent/JP3361257B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11129706A (en) | 1999-05-18 |
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